Photopolymerizable organopolysiloxane compositions having SiC-bonded acryloxyalkyl groups or methacryloxyalkyl groups as well as mercaptoalkyl groups are described in U. S. Pat. No. 4,290,869 to Pigeon. This patent discloses in column 8, lines 36 to 38, that such compositions have a stability of approximately 48 hours in closed and nontransparent containers.
It is, therefore, an object of the present invention to provide crosslinkable organopolysiloxanes which can be stored in closed containers for at least 6 months with the exclusion of light, especially ultraviolet light and have a sufficiently low viscosity prior to crosslinking that they flow into a relatively narrow fissure. Another object of the present invention is to provide stable crosslinkable organopolysiloxanes that can be stored for long periods of time in the absence of light and can be dispensed as a one-component composition without the necessity of using metering devices such as employed with a two-component composition. Still another object of the present invention is to provide crosslinkable organopolysiloxanes which do not crosslink in the apparatus used in preparing the organopolysiloxanes when the apparatus is not being used, thereby reducing the expenses normally incurred in cleaning the apparatus after each operation. Still another object of the present invention is to provide organopolysiloxanes which crosslink rapidly when exposed to ultraviolet light or light having a wavelength of from 400 to 600 nm. A further object of the present invention is to provide organopolysiloxanes which crosslink rapidly even as a relatively thick section when exposed to ultraviolet light or light having a wavelength of from 400 to 600 nm. A still further object of the present invention is to provide organopolysiloxanes which crosslink when exposed to ultraviolet light even in the presence of atmospheric oxygen. A still further object of this invention is to provide organopolysiloxane coatings which adhere to the substrates on which they are applied.